Video production techniques are well known in the art and are commonly used for creating lighting effects in motion pictures in the form of Pepper's ghost images. Typically a real object or an image of a subject is reflected by a partially-reflective foil that also allows a background scene to show through. From the perspective of a viewer the foil is invisible and the reflected image appears as a transparent “ghost” superimposed over the background scene.
A conventional foil used in the production of a Pepper's ghost illusion is made from a polymeric or plastic film. A preferred polymer is polyester which is used for its superior mechanical properties which are enhanced by stretching the film as it is produced. Conventional plastic foil burns easily when exposed to a naked flame and melts at high temperatures. Consequently, a conventional foil poses a safety risk and in the case of a fire the foil may melt and ignite and cause a rapid spread of flame and provide further fuel to the fire which will be dangerous to people in close proximity to the foil and may impede their safe evacuation.
Accordingly, a conventional foil should not be used as part of a lighting rig or stageset on music and theatre performances, television shows, nightclubs and other public places where local, national or international fire and safety regulations require the use of fire retardant materials. Furthermore, the response of a conventional foil to fire and heat may prevent a conventional foil being used in locations where the foil is likely to be in the proximity of heat-generating lighting or other such heat-generating equipment. This may prevent the erection of a Pepper's Ghost apparatus in confined spaces where close proximity of the foil to the lighting cannot be avoided.
In an attempt to overcome this problem manufacturers have added a fire resistant coating as an external layer on the outside of the transparent foil after the foil has been extruded or manufactured. However, the application of the external coating degrades the optical qualities of the transparent foil. In particular, the application of the external coating may result in a milky haze which makes the foil unsuitable for the Pepper's Ghost illusion. In order to be effective in delivering a quality image, the foil needs to be substantially transparent creating little or no dispersion of the light.
There are also problems associated with the present storage and transportation of the finished foil. Normally a foil is stored by placing a glue strip onto a roll core and sticking the end of the foil to the glued strip and then rolling the foil onto the core. However, the inventor has discovered that the glued strip causes a raised ridge in the foil that is carried through the rolls of the foil. This raised ridge results in deformities in the foil when it is unrolled making it unsuitable for use in creating or producing a Pepper's Ghost illusion, as the deformities/wrinkles will be evident to a viewer detracting from the illusion. The foil needs to be substantially wrinkle free and have very good optical and mechanical properties.
A number of associated problems are introduced due to the current methods of storing and transporting the foil. As described above, when the end of the foil is glued to the core of the roll, the foil is then rolled onto the core under tension, in order to prevent adjacent foil surfaces from sticking together an anti-stick filler is added during manufacture which aids in preventing the adjacent layers from sticking together. It has been found, in particular for foils comprising a flame retardant, that with a normal amount of anti-stick filler the haze of the foil is above acceptable levels of 5%. Such levels of haze once again making the foil unusable for creating lighting effects and in particular for producing the Pepper's Ghost Illusion.
Accordingly, it is desirable to provide a foil for creating lighting effects and in particular for producing the Pepper's Ghost Illusion, that has the required physical and optical properties such as being fire resistant to comply with local, national or international fire and safety regulations and/or allow the foil to be used in the proximity of heat-generating lighting or other such heat-generating equipment.